The present invention relates to the fabrication of friction elements and, in particular, to the winding of a filament, or a tape, into a generally disc-shaped preform suitable to be cured to form a friction element.
Disc-shaped friction elements, for example, are employed as the facings for clutches, the facing being secured to a backing plate, for example, by rivets. For convenience, hereinafter in this specification, reference is made only to a friction element comprising a facing for a clutch, but it will be understood that, where appropriate, such references to a facing for a clutch refer also to any friction element made by a similar process.
Many different compositions of the filaments, and tapes, have been used in winding such preforms, for example, a composition as disclosed in British patent specification No. 2,096,654.
In present methods of winding a filament, or a tape, into a generally disc-shaped preform, the filament, or tape, is guided on to a rotating face plate by a guide which is moved in a displacement plane around a path. The shade of the path is determined by a rotating cam. The winding pattern of the filament, or tape, on to the face plate can only be varied by changing the cam for one with a different profile and only relatively simple winding patterns are possible.
It is an object of the present invention to provide a method of winding a filament, or a tape, into a generally disc-shaped preform suitable to be cured to form a friction element which allows the preform to be wound without relying on the shape of a cam to determine the movement of the guide thereby enabling more complex and consistent winding patterns to be used.